Q6 of 49 Page 167

Show that the following points form an equilateral triangle A(a, 0), B(-a, 0),

let A = (a,0) B = (-a,0) and

⇒ AB =


=


AB = 2a


⇒ BC =


=


=


BC = 2a


⇒ AC =


=


=


AC = 2a


As all the sides are equal the triangle is Equilateral.


More from this chapter

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4

Check whether (5, -2), (6, 4) and (7, 2) are the vertices of an isosceles triangle.

 5

In a class room, 4 friends are seated at the points A, B, C and D as shown in Figure. Jarina and Phani walk into the class and after observing for a few minutes Jarina asks Phani “Don’t you notice that ABCD is a square?” Phani disagrees.

Using distance formula, find which of them is correct. Why?


 7

Prove that the point (-7, -3), (5, 10), (15, 8) and (3,-5) taken in order are the corners of a parallelogram. And find its area.

 8

Show that the points (-4, -7), (-1, 2), (8, 5) and (5, -4) taken in order are the vertices of a rhombus.

(Hint: Area of rhombus product of its diagonals)